High Antiproliferative Activity Research Articles

Discovery of novel 2,4-disubstituted pyrimidines as Aurora kinase inhibitors

In order to explore novel Aurora kinase inhibitors, a series of novel 2,4-disubstituted pyrimidines were designed, synthesized and evaluated their in vitro anti-proliferative activities against a panel of cancerous cell lines (A549, HCT-116 and MCF-7). Among them, compound 12a showed the moderate to high anti-proliferative activities against A549 (IC50 = 12.05 ± 0.45 μM), HCT-116 (IC50 = 1.31 ± 0.41 μM) and MCF-7 (IC50 = 20.53 ± 6.13 μM) cells, as well as the Aurora A and Aurora B inhibitory activities with the IC50 values of 309 nM and 293 nM, respectively. Furthermore, compound 12a induced apoptosis by upregulated the pro-apoptotic proteins Bax and decreased the anti-apoptotic protein Bcl-xl in HCT-116 cells. Moreover, the molecular docking study showed that compound 12a had good binding modes with Aurora A and Aurora B and the bioinformatics prediction discovered that compound 12a exhibited good drug likeness using SwissADME. Taken together, these results indicated that 12a may be a potential anticancer compound that was worthy of further development as Aurora kinase inhibitor.

Chemical profile, antiproliferative, antioxidant, and enzyme inhibition activities and docking studies of Cymbopogon schoenanthus (L.) Spreng. and Cymbopogon nervatus (Hochst.) Chiov. from Sudan.

Essential oils from the inflorescence of Cymbopogon schoenanthus and C. nervatus growing in Northern Sudan were examined for their chemical composition, antiproliferative activity against human breast carcinoma and human colon adenocarcinoma cell lines, antioxidant activity (phosphomolybdenum, antiradical, reducing power, and ferrous chelating), and enzyme inhibition activity against acetylcholinesterase butyrylcholinesterase, tyrosinase, α-glucosidase, and α-amylase. In silico study on the inhibition of tyrosinase and α-amylase was also performed. Piperitone (59.1%) and isomers of para-menthadienols (35.3%) were the main compounds in C. schoenanthus and C. nervatus oils, respectively. Oil from C. nervatus possessed higher antioxidant activity than that from C. schoenanthus except for its metal chelating ability. Both oils showed high antiproliferative activity. In silico study showed that trans-p-mentha-2,8-dien-1-ol and piperitone (both isomers) revealed the best docking scores for α-amylase and tyrosinase, respectively. In conclusion, oils from these two Cymbopogon species could be new natural agents with functional properties for food, cosmetics, and pharmaceutical industries. PRACTICAL APPLICATIONS: Recently, there is a growing tendency to replace synthetic oils by natural ones in the cosmetic, food, and pharmaceutical products. In this context, we investigated the chemical characterization and biological activities of two Cymbopogon species essential oils (C. schoenanthus (L.) Spreng. and C. nervatus). Antioxidant capacity, enzyme inhibition, and antiproliferative effects were tested for biological activities. Chemical characterization was identified by GC-MS. Based on our findings, the Cymbopogon species may be utilized as sources of natural bioactive agents in food industries.

Synthesis and in vitro antitumor evaluation of honokiol derivatives

Honokiol is a natural bioactive neolignan and has been widely researched and structural modified as an anticancer agent. In this paper, 18 honokiol derivatives were synthesized and investigated for their antitumor activity. Among these, the promising compound 5a exhibited much higher anti-proliferative activity with IC50 value of 10.41 μM. Transwell assays showed that 5a could significantly inhibit the invasion and migration of I-10 cells at 2.5 μM, which was further confirmed by the western blotting experiments with down-regulation of the HIF-1α and its associated downstream proteins MMP-2 and MMP-9. Overall, these results provided useful suggestion for further structural optimization of honokiol derivatives.

N-alpha-Aminoacyl Colchicines as Promising Anticancer Agents.

In the last years, many efforts have been made to find colchicine derivatives with reduced toxicity. Additionally, the deregulation of amino acid uptake by cancer cells provides an opportunity to improve anticancer drug effectiveness. To design new colchicine derivatives with reduced cytotoxicity and enhanced selectivity by means of introducing aminoacyl groups. 34 colchicine analogues bearing L- and D-amino acid pendants were synthetized and characterized by NMR, IR and MS techniques. Cytotoxicity and antimitotic properties were assessed by spectrophotometry and cell cycle assays. Oncogene downregulation was studied by RTqPCR whereas in vivo studies were performed in SCID mice. Compounds exhibit high antiproliferative activities at the nanomolar level while being, in general, less cytotoxic than colchicine. Most compounds inhibit the polymerization of tubulin in a way similar to colchicine itself, with L-amino acid derivatives being the most active in the inhibition of tubulin polymerization. All selected compounds caused cell cycle arrest at the G2/M phase when tested at 1 μM. More specifically, Boc-L-proline derivative 6 arrested half of the population and showed one of the highest Selectivity Indexes. Derivatives 1 (Boc-glycine), 27 (D-leucine) and 31 (Boc-glycine-glycine) proved fairly active in downregulating the expression of the c-Myc, hTERT and VEGF oncogenes, with compound 6 (Boc-L-proline) having the highest activity. This compound was shown to exert a potent anti-tumor effect when administered intraperitoneally (LD50 > 100 mg/kg for 6, compared with 2.5 mg/kg for colchicine). Compound 6 offers an opportunity to be used in cancer therapy with less toxicity problems than colchicine.

Fabrication of nanoparticles from a synthesized peptide amphiphile as a versatile therapeutic cargo for high antiproliferative activity in tumor cells.

Nanoparticles with encapsulated small molecules have attained vital importance in anticancer research. Peptide-based nanoparticles show their versatility in drug delivery due to their excellent biocompatibility and nontoxic nature. We demonstrate here the design and fabrication of peptide-based nanoparticles as dual-therapeutic cargo for the controlled release of hydrophilic 5-Fluorouracil (5Fu) and hydrophobic camptothecin (CPT), simultaneously. The covalent conjugation of 5Fu with the peptide, through a stimuli-responsive linker, provided better control over the release of 5Fu and dramatically reduced the possibility of leaching of the small molecule. As anticipated, the peptide-5Fu nanoparticles were efficient to encapsulate a second chemotherapeutic molecule CPT in its hydrophobic region. The stimuli-responsive release of 5Fu was carefully monitored by HPLC, NMR, and UV-visible spectroscopy. On the other hand, the release of the hydrophobic drug CPT from the nanoparticles was determined to be in a diffusion-controlled fashion. Assessment of performance in human cervical HeLa cell lines demonstrated the peptide-drug nanoparticles to be highly nontoxic. Whereas, the simultaneous release of the two antitumor agents, in a controlled manner, resulting in rapid antiproliferation of the tumor cells.

Zn(II) and Co(II) derivatives anchored with scorpionate precursor: Antiproliferative evaluation in human cancer cell lines

A ‘scorpionate’ type precursor [bdtbpza = bis(3,5-di-t-butylpyrazol-1-yl)acetate] has been employed to synthesize two mononuclear ZnII and CoII derivatives, namely [Zn(bdtbpza)2 (H2O)2]·2.5CH3OH·2[(CH3)3C-C3H2N2-C(CH3)3] (1) and [Co(bdtbpza)2(CH3OH)4] (2) in good yield. Single crystal X-ray diffraction analysis reveals that in 1, the ZnII atom is tetrahedrally surrounded by a pair of Oacetate atoms of two bis(pyrazol-1-yl)acetate units and two water molecules; while in 2, the CoII atom shows an octahedral environment coordinating a pair of Oacetate atoms of two bis(pyrazol-1-yl)acetate units along with four methanol molecules. The EPR spectra of 2 recorded at 77 and 298 K confirmed the tetragonal symmetry of the high spin Co(II). The DFT (Density functional theory) computation is in good agreement with the geometry proposed for compounds 1 and 2. Both the compounds display a high antiproliferative activity against HCT116 (colorectal carcinoma) and A2780 (ovarian carcinoma) cell lines compared to human normal dermal fibroblasts. In the case of A2780 cells, compounds 1 and 2 exhibit IC50 values that are similar to those described for cisplatin, a widely used chemotherapeutic drug. Exposure of A2780 cells to the IC50 concentration of each compound led to an increase of the number of apoptotic and autophagic cells. In the case of compound 1, the accumulation of intracellular ROS (Reactive oxygen species) is responsible for triggering A2780 cell death.

Design, synthesis and biological research of novel N-phenylbenzamide-4-methylamine acridine derivatives as potential topoisomerase I/II and apoptosis-inducing agents.

A series of novel N-phenylbenzamide-4-methylamine acridine derivatives were designed and synthesized based initially on the structure of amsacrine (m-AMSA). Molecular docking suggested that the representative compound 9a had affinity for binding DNA topoisomerase (Topo) II, which was comparable with that of m-AMSA, and furthermore that 9a could have preferential interactions with Topo I. After synthesis of 9a and analogues 9b-9f, these were all tested in vitro and the synthesized compounds displayed potent antiproliferative activity against three different cancer cell lines (K562, CCRF-CEM and U937). Among them, compounds 9b, 9c and 9d exhibiting the highest activity with IC50 value ranging from 0.82 to 0.91 μM against CCRF-CEM cells. In addition, 9b and 9d also showed high antiproliferative activity against U937 cells, with IC50 values of 0.33 and 0.23 μM, respectively. The pharmacological mechanistic studies of these compounds were evaluated by Topo I/II inhibition, western blot assay and cell apoptosis detection. In summary, 9b effectively inhibited the activity of Topo I/II and induced DNA damage in CCRF-CEM cells and, moreover, significantly induced cell apoptosis in a concentration-dependent manner. These observations provide new information and guidance for the structural optimization of more novel acridine derivatives.

New cytotoxic bio‐transformed sesquiterpene by Rhizopus oryzae fungus

Due to the rapidly increasing number of pathogenic bacteria, viruses, and tumor cells that possess resistance toward established therapies, lead structures for the development of new drugs are in high demand. The plant material of Tanacetum sinaicum is considered a prolific source of the potent biologically active sesquiterpene Tanacetolide A (1). In our research, we focused on the structural transformation of the substrate Tanacetolide A (compound 1) by suspended culture of the novel locally isolated terrestrial fungus Rhizopus oryzae KX685359. The fungal transformation resulted in the formation of 1β,3α‐dihydroxy‐6α‐hydroperoxy‐eudsm‐4(15)‐ene 12‐oic acid (2) with higher antiproliferative activity against colon cancer cell line (Caco‐2) than that of the parent compound (1).

Design of a potent anticancer lead inspired by natural products from traditional Indian medicine

Among the plant constituents of Clerodendrum colebrookianum Walp., acteoside, martinoside, and osmanthuside β6 interact with ROCK, a drug target for cancer. In this study, aglycone fragments of these plant constituents (caffeic acid, ferulic acid, and p-coumaric acid) along with the homopiperazine ring of fasudil (standard ROCK inhibitor) were used to design hybrid molecules. The designed molecules interact with the key hinge region residue Met156/Met157 of ROCK I/II in a stable manner according to our docking and molecular dynamics simulations. These compounds were synthesized and tested in vitro in SW480, MDA-MB-231, and A-549 cancer cell lines. The most promising compound was chemically optimized to obtain a thiourea analog, 6a (IC50 = 25 µM), which has >3-fold higher antiproliferative activity than fasudil (IC50 = 87 µM) in SW480 cells. Treatment with this molecule also inhibits the migration of colon cancer cells and induces cell apoptosis. Further, SPR experiments suggests that the binding affinity of 6a with ROCK I protein is better than that of fasudil. Hence, the drug-like natural product analog 6a constitutes a highly promising new anticancer lead.Communicated by Ramaswamy H. Sarma

Vanadium(V) tris-3,5-di-tert-butylcatecholato complex: Links between speciation and anti-proliferative activity in human pancreatic cancer cells

Vanadium complexes are intensively tested for anti-cancer activities, particularly for the novel treatment protocols involving injections of cytotoxic compounds directly into the tumor. This approach is increasingly applied to difficult-to-treat cancers, such as pancreatic cancer. The first study of in-vitro anti-cancer properties of a rare stable non-oxido V(V) complex, (NH4)[V(dtbc)3], where dtbcH2 is 3,5-di-tert-butylcatechol, was performed by a combination of end-point viability assays and real-time (IncuCyte) proliferation and cytotoxicity assays in human pancreatic cancer (PANC-1) cells. An improved synthetic procedure led to a nearly quantitative yield of the complex under ambient conditions. Reactions of (NH4)[V(dtbc)3] either in polar organic solvents or in neutral aqueous media led to the formation of V(V)-oxido-catecholato intermediates (characterized by electrospray mass spectrometry) that were responsible for its anti-proliferative and cytotoxic (apoptotic or necrotic) activity (IC50, 3.5–18 μM V in 72 h assays). These results demonstrate the link between solution speciation and biological activity of V complexes. Reaction of (NH4)[V(dtbc)3] with human serum albumin (HSA) in aqueous media led to the formation of protein-bound V(V) oxido-catecholato species that showed high anti-proliferative activity (IC50 ~10 μM V) combined with low cytotoxicity. Formation of HSA adducts of hydrophobic V complexes, such as (NH4)[V(dtbc)3], is a promising way to achieve their sustained delivery to cancer tumors.

Identification of Novel Resorcinol Amide Derivatives as Potent and Specific Pyruvate Dehydrogenase Kinase (PDHK) Inhibitors.

Pyruvate dehydrogenase kinases (PDHKs) promote abnormal respiration in cancer cells. Studies with novel resorcinol amide derivatives based on VER-246608 (6) led to the identification of 19n and 19t containing five-membered heteroaromatic rings as unique structural features. These substances possess single-digit nanomolar activities against PDHKs. 19t exhibits higher potencies against PDHK1/2/4 than does 6 and inhibits only PDHKs among 366 kinases. Moreover, 19g, 19l, and 19s were found to be isotype-selective PDHK inhibitors. Molecular dynamics simulations provide a better understanding of how the heteroaromatic rings affect the activities of 19n and 19t on PDHK1/2/3/4. Moreover, 19n possesses a much higher antiproliferative activity against cancer cells than does 6. We demonstrated that the results of PDH assays better correlate with cellular activities than do those of PDHK kinase assays. Furthermore, 19n induces apoptosis of cancer cells via mitochondrial dysfunction, suppresses tumorigenesis, and displays a synergistic effect on satraplatin suppression of cancer cell proliferation.

An integrated approach for the valorization of mango seed kernel: Efficient extraction solvent selection, phytochemical profiling and antiproliferative activity assessment.

A novel valorization strategy is proposed in this work for the sustainable utilization of a major mango processing waste (i.e. mango seed kernel, MSK), integrating green pressurized-liquid extraction (PLE), bioactive assays and comprehensive HRMS-based phytochemical characterization to obtain bioactive-rich fractions with high antioxidant capacity and antiproliferative activity against human colon cancer cells. Thus, a two steps PLE procedure was proposed to recover first the non-polar fraction (fatty acids and lipids) and second the polar fraction (polyphenols). Efficient selection of the most suitable solvent for the second PLE step (ethanol/ethyl acetate mixture) was based on the Hansen solubility parameters (HSP) approach. A comprehensive GC- and LC-Q-TOF-MS/MS profiling analysis allowed the complete characterization of the lipidic and phenolic fractions obtained under optimal condition (100% EtOH at 150 °C), demonstrating the abundance of oleic and stearic acids, as well as bioactive xanthones, phenolic acids, flavonoids, gallate derivatives and gallotannins. The obtained MSK-extract exhibited higher antiproliferative activity against human colon adenocarcinoma cell line HT-29 compared to traditional extraction procedures described in literature for MSK utilization (e.g. Soxhlet), demonstrating the great potential of the proposed valorization strategy as a valuable opportunity for mango processing industry to deliver a value-added product to the market with health promoting properties.

Iron(III) and nickel(II) complexes of tetradentate thiosemicarbazones: Synthesis, structure, cytotoxicity, and lipophilicity.

Eighteen of the iron(III) and nickel(II) complexes with tetradentate thiosemicarbazidato ligands were synthesized and described, by analytical and spectroscopic methods. Two complexes as an example to the iron and nickel centered ones were crystallographically analyzed to confirm the molecular structures. Cytotoxic effects of the complexes on K562 chronic myeloid leukemia cells were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. For comparison, human umbilical vein endothelial cells (HUVECs) was used as a noncancerous cell line. While four of the iron(III) complexes exhibited the antileukemic effect with 50% inhibition of cell growth (IC50 ) values in the 3.4 to 6.9 μg/mL range on K562 cell line, the nickel(II) complexes showed no significant effect on both cell lines. The complexes Fe4, Fe5, and Fe6, bearing 4-methoxy substituent exhibited relatively high antiproliferative activity on both cell lines. Complex Fe3 with 3-methoxy and S-allyl groups exhibited a selectivity between K562 and HUVEC cells by IC50 values of 6.9 and >10 μg/mL, respectively. Lipophilicity, a key parameter for bioavailability and oral administration, was found in the range of -0.3 and +1.3 that desired for drug active ingredients. The results were discussed in the context of a structure-activity relationship.

Toxicological and pharmacological properties of essential oils of Calamintha nepeta, Origanum virens and Thymus mastichina of Alentejo (Portugal)

Three autochthonous flavouring herbs from Alentejo (Portugal), Calamintha nepeta (syn. Clinopodium nepeta), Origanun virens and Thymus mastichina, were selected to evaluate toxicological, antioxidant, antiproliferative and antimicrobial potential of their essential oils (EOs). C. nepeta and T. mastichina EOs showed a high content of oxygenated monoterpenes (86–91%) while O. virens had similar content of oxygenated and hydrocarbon monoterpenes (45%). Toxicological assessment suggests high activity against A. salina (31.8 < CL50 < 128.4 mg/L) and very low toxicity in Swiss mice (DL50 ≥ 1500 mg/kg). EOs showed high antioxidant ability by DPPH radical scavenging assay (0.1–0.6 mg QE/mL EO), total reducing power method (0.2–1.7 mg QE/mL EO) and β-carotene/linoleic acid system (11–501 mg QE/mL EO). An important antiproliferative effect against human breast tumour cell line was observed (88.9 < EC50 < 108.5 mg/L). Moreover, EOs presented a large antibacterial spectrum. Results point out the low toxicity and high antioxidant, antiproliferative and antimicrobial activities of EOs of these endemic aromatic plants, suggesting their potential use in biotechnological, food and/or pharmaceutical industries.

In vitro anti-proliferative and anti-bacterial properties of new C7 benzoate derivatives of pinocembrin

In the present work, the in vitro anti-proliferative and anti-bacterial activities of three semi-synthetic benzoate pinocembrin derivatives, isolated from the aerial parts of Glycyrrhiza glabra L., were investigated. As occurs in most natural compounds, the bioavailability of pinocembrin is very poor, therefore it should be improved by chemical strategies aimed to prolong its shelf life and, consequently, its activity. On this basis, three benzoate derivatives of pinocembrin (a1–a3) were synthesised and assayed in order to ascertain their biological value. Among them, compound a1 showed the highest anti-proliferative activity on a wide panel of cancer cell lines, as well as low toxic effects on non-malignant breast cells. The calculated IC50 values in HeLa and SKBR3 cells were 8.5 and 12.7 µM, respectively. Briefly, a1 treatment increased ROS levels, induced mitochondrial membrane damage leading to necrotic death of HeLa cells. Moreover, a1 displayed a promising anti-bacterial activity.

English

The medicinal plants Annona senegalensis Pers. and Allophylus africanus P Beauv. are used in Tanzania traditional medicine for the treatment of cancer. However, there is no scientific documentation on their therapeutic effectiveness. The present study evaluated antiproliferative potential as an indicator of anticancer activity of A. senegalensis and A. africanus plant species from Tanzania. A. senegalensis and A. africanus were collected from Ugweno village at Kilimanjaro, Tanzania. Different types of extracts were prepared in dichloromethane/methanol (DCM:MeOH), petroleum ether, DCM, ethyl acetate (EtOAc), MeOH and water respectively. Antiproliferative activity against HCC 1396 (breast), HEp-2 (throat) and CT 26 (colon) cancer cell lines was assessed by the MTT cell viability assay. The results of the present study showed that the antiproliferative activity varied between plant extracts and the cancer cell lines. The highest antiproliferative activity was achieved with petroleum ether extract of A. senegalensis against HEp-2 with an IC50 value of 0.42 ± 0.09 μg/ml. This also depicted the highest selectivity to cancerous cells (SI value 94.19) compared to the other extracts. A. africanus also depicted good antiproliferative activity against HEp-2 with IC50 values of 1.00 ± 0.41 and 2.37 ± 1.45 μg/ml for DCM:MeOH and petroleum ether extracts, respectively. The findings validate the traditional use of A. senegalensis and A. africanus in the treatment of cancer. Results also support previous studies which demonstrated the effect of extraction solvent used in extraction of bioactive agents from medicinal plants. Further studies involving the isolation of pure antiproliferative compounds against cancer cells from the two plants are recommended to elucidate bioactive molecules. Key words: Annona senegalensis, Allophylus africanus, antiproliferative, cancer cells, plant extracts.

Abstract 4825: Preclinical characterization of BAY-924, a first in class ADC targeting CXCR5-positive B-cell malignancies, with a KSP inhibitor as novel payload

Abstract Despite recent progress in the treatment of B-cell malignancies, patients are still in need of innovative therapeutic approaches. CXCR5 is a chemokine receptor expressed in a majority of B-cell malignancies including diffuse large B-cell lymphoma (DLBCL), Mantle cell lymphoma (MCL), follicular lymphoma and chronic lymphocytic leukemia. Evaluation of tumor biopsies from relapsed DLBCL patients shows that CXCR5 staining remains high, suggesting altogether that it could be a relevant target to explore for the treatment of non-Hodgkin lymphoma. BAY-924 is a novel first-in-class antibody drug conjugate (ADC) consisting of a humanized anti-CXCR5 IgG1 antibody (Ab) linked to a potent proprietary kinesin spindle protein inhibitor (KSPi). Of importance, the structure of the ADC is optimized for a specific metabolism, matching the KSPi mode of action and enabling a maximal retention of the payload within the tumor cells (Lerchen HG et al.; Angew. Chem. Int. Ed, 2018). Surface plasmon resonance assay showed a high binding affinity of the Ab to CXCR5 (2.5 nM). Affinities of 0.8 to 10 nM were measured by flow cytometry for the ADC in different CXCR5+ lymphoma cell lines. In vitro, BAY 924 had high and selective anti-proliferative activity in a panel of tumor cell lines with different levels of CXCR5 expression (&amp;lt;0.03 - 2 nM IC50). Efficient internalization and lysosomal co-localization of the Ab was observed in a variety of cell lines including the CXCR5+ MCL REC-1 cells. In vivo, BAY-924 was highly active in several CXCR5+ lymphoma models with a specific accumulation of the payload in tumor versus liver, spleen and kidney and almost undetectable levels in plasma. In the REC-1 model implanted subcutaneously (SC) in mice and treated at large tumor size (500 mm3), long lasting tumor regression was observed after 2 intravenous injections of BAY 0924 at 10 mg/kg, Q7D, whereas the model was insensitive to ibrutinib, a current standard of care (SoC) for the MCL indication. In the advanced ABC DLBCL model OCI-LY1 (SC), a single injection of BAY-924 at 10 mg/kg induced complete responses in 10/10 mice (up to day 95 post-treatment). In this model, head-to-head comparison showed superior activity of BAY-924 compared to the SoCs rituximab (R)-CHOP, R/bendamustine and R/lenalidomide. Also, BAY-924 induced potent antitumor effect with a 4% ΔT/ΔC (day 55) in the ABC DLBCL OCI-Ly3-2b model, expressing weak to moderate levels of CXCR5 in vivo. Given its unique structure, and based on supportive data from other projects, it is anticipated that BAY-924 shows a favorable safety profile, due to the high stability of the ADC and a non-cell permeable free payload which is trapped inside the tumor cells. Overall, these results support further development of BAY-924 as an innovative approach for the treatment of CXCR5+ non-Hodgkin lymphoma. Citation Format: Sarah Johannes, Stefanie Hammer, Stephan Maersch, Hans-Georg Lerchen, Beatrix Stelte-Ludwig, Hannah Joerissen, Oliver von Ahsen, Christoph Schatz, Simone Greven, Christoph Mahlert, Dominik Mumberg, Pascale Lejeune. Preclinical characterization of BAY-924, a first in class ADC targeting CXCR5-positive B-cell malignancies, with a KSP inhibitor as novel payload [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4825.

A New Synthetic Spiroketal: Studies on Antitumor Activity on Murine Melanoma Model In Vivo and Mechanism of Action In Vitro.

In a previous study, we synthesised a new spiroketal derivative, inspired to natural products, that has shown high antiproliferative activity, potent telomerase inhibition and proapoptotic activity on several human cell lines. This work focused on the study of in vivo antitumor effect of this synthetic spiroketal on a murine melanoma model. In order to shed additional light on the origin of the antitumor effect, in vitro studies were performed. Spiroketal was administered to B16F10 melanoma mice at a dose of 5 mg/Kg body weight via intraperitoneum at alternate days for 15 days. Tumor volume measures were made every 2 days starting after 12 days from cells injection. The effects of the spiroketal on tumor growth inhibition, apoptosis induction, and cell cycle modification were investigated in vitro on B16 cells. HIF1α gene expression, the inhibition of cells migration and the changes induced in cytoskeleton conformation were evaluated. Spiroketal displayed proapoptotic activity and high antitumor activity in B16 cells with nanomolar IC50. Moreover it has shown to inhibit cell migration, to strongly reduce the HIF1α expression and to induce strongly deterioration of cytoskeleton structure. A potent dose-dependent antitumor efficacy in syngenic B16/C57BL/6J murine model of melanoma was observed with the suppression of tumor growth by an average of 90% at a dose of 5 mg/kg. The synthesized spiroketal shows high antitumor activity in the B16 cells in vitro at nM concentration and a dose-dependent antitumor efficacy in syngenic B16/C57BL/6J mice. The results suggest that this natural product inspired spiroketal may have a potential application in melanoma therapy.

Synthesis and Reactivity of 6,8-Dibromo-2-ethyl-4H-benzo[d][1,3]oxazin-4-one Towards Nucleophiles and Electrophiles and Their Anticancer Activity.

The genetic heterogeneity of tumor cells and the development of therapy-resistant cancer cells in addition to the high cost necessitate the continuous development of novel targeted therapies. In this regard, 14 novel benzoxazinone derivatives were synthesized and examined for anticancer activity against two human epithelial cancer cell lines; breast MCF-7 and liver HepG2 cells. 6,8-Dibromo-2- ethyl-4H-benzo[d][1,3]oxazin-4-one was subjected to react with nitrogen nucleophiles to afford quinazolinone derivatives and other related moieties (3-12). Benzoxazinone 2 responds to attack with oxygen nucleophile such as ethanol to give ethyl benzoate derivative 13. The reaction of benzoxazinone 2 with carbon electrophile such as benzaldehyde derivatives afforded benzoxazinone derivatives 14a and 14b.The structure of the prepared compounds was confirmed with spectroscopic tools including IR, 1H-NMR, and 13C-NMR. Derivatives 3, 9, 12, 13, and 14b exhibited high antiproliferative activity and were selective against cancer cells showing no toxicity in normal fibroblasts. Derivative 3 with NH-CO group in quinazolinone ring was effective only against breast cells, while derivative 12 with NH-CO group in imidazole moiety was only effective against liver cells probably through arresting cell cycle and enabling repair mechanisms. The other derivatives (9, 13, and 14b) had broader antiproliferative activity against both cell lines. These derivatives enhance the expression of the p53 and caspases 9 and 3 to varying degrees in both cell lines. Derivative 14b caused the highest induction in the investigated genes and was the only derivative to inhibit the EGFR activity. The unique features about derivative 14b could be attributed to its high lipophilicity, high carbon content, or its extended conjugation through planar aromatic system. More investigations are required to identify the lead compound(s) in animal models.

Discovery of tropinone-thiazole derivatives as potent caspase 3/7 activators, and noncompetitive tyrosinase inhibitors with high antiproliferative activity: Rational design, one-pot tricomponent synthesis, and lipophilicity determination

We have designed novel tropinone-thiazole derivatives that showed high antiproliferative activity against a variety of cancer cell lines via caspase 3/7 activation mechanism. Among the derivatives, compounds 3b-3h were found to exhibit high activity against human leukemia (MV4-11), human lung carcinoma (A549), human breast carcinoma (MCF-7), and skin melanoma (B16–F10) cancer cell lines, with IC50 values of 5.43–11.06 μM. The lead compound 3g increases caspase 3/7 activity in A549 cells 25 times more than the control, and 2 times more than reference drug camptothecin. We have also found that tropinone-thiazole derivatives exhibit high tyrosinase inhibitory activity. The lead compounds 3g and 3h showed tyrosinase inhibition effect, with IC50 values 3.22 and 3.51 μM, respectively. These inhibitory activities are 22 times higher than the activity of kojic acid (IC50 72.27 μM) and 120 times higher than activity of ascorbic acid (IC50 386.5 μM). For compounds 3g and 3h, the experimentally determined lipophilicity correlates very well with their enzymatic activities. These data suggest that presented compounds could constitute lead anticancer drug candidates.